Sludge treatment process and product



F. SALATHE. SLU-DGE TREATMENT Pocess Aun PRODUCT. APPLICATION FILED MAR. 26, 1921. 1 ,409,590. Pfltll'd Mar. 14, 1922.

v 3 SHEETS-SHEET l- F. SALATHE.

SIUDGE TREATMENT PROCESS AND PRODUCT.

APPLICATION FILED MAR'. 26, T921.

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F. SALATHE.

SLUDGE .TREATMENT- PROCESS AND`PRODUCT. APPLICATION FILEn'MAR. 26. 1921.

Patented Mar. 14, 1922.

3 SHEETSQSHEET 3.

SOL VENT' CONDE/V667? TURNTHBLE UNITED STAT-Es PALI'ENT OFFICE.

FREDERICK SALATHE, or CHICAGO, ILLINOIS, AssIGNoR or DNB-HALF To THE WESTERN GAS CONSTRUCTIONCOMPANY, OF FORT PORATION 0F INDIANA.

WAYNE, INDIANA, A COB,-

SLUDGE TREATMENT PROCESS AND PRODUCT.

Application filed March 26, 1921.

is a specification.

This invention relates to the treatment of sludges, such for example as are obtained as residues from the acid treatment of crude oil lubricating stocks; important objects ofA the invention are to effect an efficient and substantially complete recovery from such sludges of acid of a high degree of concentration, to recover' also the reagent employed in separating the acid from the sludge, the recovered reagent being in a form so that it is available for further sludge treatment, and to produce, in the carrying out of the improved sludge treatment process, a valuable hydrocarbon productA having a wide range of industrial uses. l

In addition to the general objects'recited above, the invention has for further objects such other improvements or advantages in operation and results as are found to obtain in the improved process andk product hereinafter described 0r claimed.

In the accompanying drawings, forming la partof this specification and showing, for

purposes of exemplication, a preferred form of apparatus yinwhich the invention may be practiced, but without limiting the claimed invention to such illustrative instance or instances: 4

Figures l, la and lb collectively illustrate a diagrammatic representation of apparatus for carrying out the improved sludge treatment process of the present invention.

In its present embodiment, the invention is applied to the treatment of sludges obtained from crude oil lubricating stocks, and for convenience, the present descriptionwill be confined to this use of the invention. The features of the invention are, however, susceptible of other lvaluable applications; consequently the scope of the inventionis not confined to the specific use and specific embodiment herein described as an illustrative example.

In the art of refining crude oils for the production-of the various commercial products, a residue available as a lubricating Specification of Letters Patent.

Patented Mar. 14., 1922. smal No. 455,802.

stock remains after the gasolines, kerosenes and other .light oils have been driven off. This lubrlcating stock, or the distillates therefrom, is' usually subjected to a refinin process in which it is treated with an aci lsuch as sulphuric acid, in an agitator. As a result of the acid treatment of the lubricating stock, an acid tarry sludge is precipitated,.wh1ch is separated from the refined oil. This acid sludge has a highly complex compositlon and contains the sulphuric acid partially in a mechanical mixture with other constituents of the sludge and partially in the form of chemical combinations resulting from polymerization of the unsaturated hydrocarbons which must be eliminated from thelubricating stock by the acid treatment.

The compositionof the sludge varies'with the character of the crude oil from which the lubricating stock is derived, and is thus incapable of positive definition as to the entire number or proportion of its constituent elements' or compounds. However. such sludges contain, in addition to the acid, polymerized hydrocarbons, sulphonated hydrocarbons and oxidized hydrocarbons in an intimate mixture.. The disposal of this sludge is a serious problem to the oil refiner, becauseof the acid character the sludge and its consequent destructive properties. Processes have been employed for the purpose of recovering the unused acid which is vmechanically held in the sludge. These processes contemplate subjecting the sludge to a water wash to such an extent that the tarry matters contained in the sludge are oated out, after which the acid is allowed to settle out by gravity. The separation of the acid from the Water is then effected by a decanting process. Such water wash treatment of acid sludges, for the recovery of the acid is, however, open to the serious disadvantage, that the acid recovered `is of and which is -practically valueless for fur ther industrial use. Even'in the case of sludges which do not have this tendency to emulsify completely, the separated tarry compounds will always retain a percentage of acid water which is not only diiicult to remove but forms other compounds, by

hydrolysis with some of the hydrocarbon constituents of the sludge.

The present invention comprehends the treatment ofsludges, such as :mentioned above, by an improved proce which removes substantially the ,entire content of acid from the sludge and effects the immediate recovery of the acid in a highly concentrated form, as contradistinguished from v the acid of low concentration obtained by former processes and also produces a valuable.

product capable of wide industrial use, and of especial utility as a constituent oflacquers or paints, or for employment as av roofing material. Referring to the drawings which illustrate an embodiment of apparatus for carrying out the improved process of the invention and for obtaining the new product hereinafter described, there is shownat 11 an agitator of the usual type employed for the acid refining treatment of crude oil lubricatin stocks, ory their distillates. A quantity ofubricating stock, for example, is charged --into the agitator 11' and is therein-subjected or lubricating distillates and acid has progressed'for about 30 to 40 minutes in the air agitatoi` .11, the agitation is discontinued and the contents of the 'agitator are allowed to standfor labout three hours. stocks include reduced lubricating oil left as residue in the still. The air employed in -the agitation process exerts 'a slight oxidizing,eifectyon the mixture-and the oxidized products are taken up by the sludge,

When the settling` period has been completed, the rened oil is drawn olf from the top of thesettled mixture and the acid sludge vwhich settles out in the bottom of the agitator may be drawn olf through ay valvecontrolled sludge pipe 416 into sludge buckets 17 carried by a' crane hoist 18' and having provision for swinging the filled d sludge buckets 17 over and dumping their contents into a mixer 19.*

The mixer 19 is preferably ofthe mechanical type, in which agitation of the material Lubricating deposited in the mixer is effected by means of paddles 20 secured to a vertical shaft I21. This shaft 21 may be driven by suitable driving and power connections indicated generally at 22. In accordance with the invention, the sludge discharged into the mixer from the sludge buckets 17 is thoroughly agitated with a hydrocarbon solvent, of the aromatic hydrocarbon series, preferably in equal proportion by volume with the sludge deposited in the mixer. Solvent naphtha, a product from the coal tar distillation, is a satisfactory solvent for 'this purpose, and, in fact, it is preferable to employ a solvent naphtha,`the boiling point of which ranges between 250o F. and 400 F. However, the invention is not limited to the particular -hydrocarbon solvent herein mentione-d, nor to solvent naphtha withinthe above stipulated range of boiling points, since other Solvents, including naphthas having different boiling points may be employed. The solvent is supplied to the mixer 19 from a solvent line 23.l

The agitation-of the sludge and solvent isl continued in the mixer'19. until substantially the entire quantity ofthe hydrocarbon constituents of the sludge are in solution.' Ordinarily this will require an agitation of about two hours for average sludges. As'

soon as then sludge solution has been obtained, the 'agitatlonis discontinued by disconnecting the power from the paddles 20 and the sludge solution is allowed to stand until the acid settles out in the bottom of the mixer, the settling usually requiring about two hours. v

As soon as the acid has settled out, it may be drawn off through a valve controlled acid line24 into an acid tank 25, in which the recovered acid may be stored for future use. By the employment of the hydrocarbon solvent, practically the entire quantity of acid in the acid sludge originally deposited in the mi er is recovered from the sludge solution. Mdi'eover, because of the fact that no water .is employed in effecting the recovery of the acid,the recovered acid, is of a high degree of concentration, approximating that of the acid employed for refining the lubricating stock in the agitator 11. For example, if the acid employed in the agitator 11 have a specific gravity of about 66 B., the acid recovered from the sludge solution shows little lossof concentration, ranging from 57 to 60 B., or even a higher degree of concentration. This highly concentrated recovered acid may-be readily further concentrated for use in the rening operation above described.

In -cases where the acid initially employed in the refiningoperation is of a higher degree of concentration, the recovered acid will show a 'likeincrease in concentration.- i

After-the acid has been recovered from the sludge'solution, the solution may be then neutralized by titrating with the neutralizing agent. A solution of soda ash (sodiumcarbonate or sodium hydrate), containing about four ounces of salt to one-or two pints of Water usually will be suficient for removing theresidual acidity in the sludge solution contained in .an agitator having a capacity of about two-hundred gallons. The neutralizing solution is supplied from a neutralizing solution egg 25 having a supply line connection-26 with the mixer. When the neutralized solution has settled out in the f bottom of the mixer 19, the waste solution is drawn oil through a valve controlled waste solution line 27.

The sludge solution left in the mixer is then discharged through a valve controlled sludge solution line 28 and pumped by a pump 29 into a still 30. The still 30 is pro-y vided With an external fire box 31 located beneath the still'and in a heating chamber 32 Which connects with a stack 33. Above the fire box 31 is a steam coil 34 adapted to be supplied With live steam from a supply-line 35 and having a valve controlled supply connection 36 with a steam manifold 37 located in the bottom of the still. The manifold 37 is provided with a plurality of branch pipes 38, each of which has steam jets, for permitting the steam to circulate through the solution in the chamber of the still. 30. When the desired quantity of sludge solution has been delivered to the still 30, the temperature is lirst raised rapidly by direct firing .to about 250o F., durlng which time the lighter portions of the solvent in the solution are distilling over and passing out through a solvent discharge line 39 into a condenser 40. Live steam is then introduced into the coil 34 and is permitted to discharge from the branch pipes 38 of the manifold 37 and to circulate through the solution within' the still. The firing is continued until all of the solvent has been distilled olf, the final temperature necessary for complete removal of the solvent depending upon the solvent used..l

The recovered solvent condenses in the condenser 40 and'next passes through a separator 41 in which the solvent is separated from the Water condensed from the steam. From the separator 41 the solvent passes through a solvent line 42 to a solvent` tank 43,'fro1n which the recovered solvent may be pumped by a pump 44 through a return line45'that delivers the solvent to a preheater 46 having a discharge connection 47 with a pump 48.

The pump 48 delivers the solvent into the4 supply line 23 leading-to the mixer 19in which the recovered solvent may .be used for further solutiontreatment of -the sludge deposited in the mixer. The solvent recovered by the process of the invention is in. exceedingly pure'form, and where solvent naphtha is employed in the original solution process in the mixer 19, a high grade White naphtha is obtained in the solvent tank43, because of the action of the acid with which the solvent is broughtintocontact in the mixer. Moreover, practically all of the solvent is recovered from the sludge solution, there being but a small percentage of loss of so-lvent.

After the distillation of the solvent in the still 30 has been completed, the still is allowed to cool off and the residue is discharged through a valve controlled discharge line 49 and deposited in containers 50 on a turntable 51. This residue from'the still is an exceedingly valuable product. It contains sulphonated hydrocarbons, polymerized hydrocarbons and oxidized hydrocarbons all in an intimate admixture, and is practically free from hydrolized hydrocarbons. The residue is further characterized by the fact that it contains substantially the entire quantity of sulphonated hydrocarbons present in the original sludge, there being no Water wash to eliminate any sulphonated hyfdrocarbons'. There is no emuls'iication of any of the polymerized hydrocarbons in the residue. Thegrelatively large quantity of sulphonated hydrocarbons present in the residue as compared with the residues obtained from Water wash treatment of sludges give a rubbery and adhesive quality to the residue-which makes it valuable as a roong or an adhesive material. It may also be employed as an ingredient of paints, varnishes or lacquers. The residue is usually quite black in color, solid at ordinary temperatures, plastic in its nature` and of great ad- 100 hesive power. It is ractically Waterproof.

A further charactertlstic of the residue obtained by the process of the present invention is that it is almostentirely soluble ,in gasoline of 60 B., for example, of approxi- 105 mately 97% solubility, whereas residues obtained from Water Wash treatment ofsludges at best only give about solubility in gasoline of like specificY gravity; the sludge obtained by the present process moreover 110 shows an iodine value of 25 to 29 Whereas residues obtained from water Wash sludges show only an iodine value of 8.

The invention as hereinabove set forth may be variously embodied Within the scope 115 of the claims hereinafter made.

Iclaim: 1

1. In a process of treating acid sludges obtained vfrom crude oils, the combination of steps that consists in: mixing and agitat- 120 ing a proportion of such sludge with a substantially equal proportion of hydrocarbon solvent to 'liberate acid having a specificy gravity of about 50 to 60 Baum; then allowing the acid to settle out from the mix- 13 0 ture and recovering such acid; then mixing a. neutralizing agent with the sludge solution to neutralize the residual acidity; then removing the neutralizing agent from the sludge solution; and then vsubjecting the 130 pheric temperatures; substantially as speci- 2. In a process of treating acid sludges obtained fromcrude oils, theV combination of steps that consists in: mixing and agitating a proportion of such Sludge with a substantially equal proportion .of solvent naphtha to liberate acid having a specific gravity of about 50 to 60` Baum; then allowing the acidto settle out from the mixture and recovering such acid; then mixing a vneutralizing agent with the sludge solution to neutralize the residual acidity; then removing the neutralizing agentA from the sludge solution; and then subjecting the sludge solution to distillation to recover the solvent naphtha and `to obtain a hydrocarbon residue containing polymerized hy` drocarbons, sulphonated' hydrocarbons and oxidized hydrocarbons; substantially as specified.

3. In a process of treating acid Hsludges obtained from crude oils, the conbination of steps-that consists in: mixing and agitatying such sludges with solventnaphtha to 'liberate the acid; then allowing the acid to settle out from the mixture and recovering .such acid; then mixing a neutralizin agent with the sludge solution to neutralize the residual acidity; then removing the neutralizing agent from the sludge solution; and then subjecting'the-sludge solution to distillation to recover the solvent naphtha and to obtain a hydrocarbon residue containing polymerized hydrocarbons, sulphonated hydrocarbons and oxidized hydrocarbons; substantially as s cified. v

4. Ina process of'treatlng acid sludges obtained from crude oils, thecombination of steps thatr consists l in: mixing such sludges ,with a hydrocarbon solvent to liberate the acid ;then allowing the acid to settle out from the mixture and. recovering such acid: then mixing a neutralizing agent with v the sludge solution to neutralize the residual acidity: then removing the neutralizing subjecting the sludge solution to distillation torecover the hydrocarbon solvent and to obtain a hydrocarbon residue containing fpolymerized hydrocarbons, sulphonated h drocarbons and oxidized hydrocarbons, su stantia-lly as specied 5. In a process of treating acid sludges obtained from crude oils, the acid in said sludges being of a specific gravity of not less than 50 Baume, the Vcombination of steps that consists in: mixing such sludges with a hydrocarbon solvent to liberate the acid without. substantial dilution thereof; then. allowing the acid to settle out from the mixture and recovering 'such acid; and then subjecting 'the sludge solution to distillation vto recover 'the hydrocarbon solvent and to obtain a hydrocarbon residue containing polymerized hydrocarbons, sulphona-ted hyi drocarbons and oxidized hydrocarbons; substantially as specified.

6. In a process of treating acid sludges vobtained from crude oils, the combination of steps that consists in: mixing and agitating a proportion of such sludge with a substantially equal proportion of hydrocarbon sol vent to liberate acid having a specific gravity of about 50 to 60 Baume; then 7. Ina process of treating acid sludges obtained from crude oils, the combination of steps that consists ini mixing and agitatlng a proportion of such sludge with a substantially equal proportion ofsolvent naphtha to liberate acid having a specific gravity of about 50 to 60 Baume; then allowing the acid to settle out from the' mixture and recovering s-uch acid; then subjecting the sludge solution to distillation to recover the solvent naphtha and'obtain a hydrocarbonresidue containing polymerized hydrocarbons, sulphonated hydrocarbons and oxiized hydrocarbons; substantially as speci- 8. In a process of treating acid slud es obtained from crude oils, the combination of steps that consists in: mixing and. agitating such sludges with solvent naphtha to liberate the ac1d; then allowing the acid to settle out from the mixture and recovering such acid; and then subjecting the sludge solution to distillation to, recover the solvent naphtha and obtain a hydrocarbon residue containing polymerized hydrocarbons, sulphonated hydrocarbons and oxidized hydrocarbons; substantially as specified.

9. In a process. of treating acid sludges obtained from crude oils, the combination of steps that consists in: mixing such sludges with a hydrocarbon solvent to liberate the acid; then allow-ing the acid tosettle out1 from the mixture and recovering such acid; and then subjecting the sludge solution 'to distillation to recoverthe hydrocarbon solventvand to obtain a hydrocarbon'residue containing polymerized hydrocarbons, sulphonated hydrocarbons and oxidized hydrocarbons; substantially as specified.

10. The process of recovering sulphuric acidfrom acid sludges obtained from crude oils, as hereinabove described, which consists in mixing and agitating a proportion of such sludge with a substantially equal proportion of solvent naphtha to liberate sulphuric acid having a specic gravity of about to 60o Baume; and then effect ing a gravity'separation of the acid from the sludge solution.

11. The process of recovering sulphuric acid from acid sludges obtained from crude oils, as hereinabove described, which consists in mixing and agitating a proportion of such sludge with a substantially equal proportion of solvent naphtha and thereby recovering` from the sludge sulphuric acid having a specific gravity of about 50o to 60 Baume.

12. rlhe process of recovering sulphuric acid from acid sludges obtained from crude oils, as hereinabove described, which consists in mixing and agitating a proportion of such sludge with a substantially equal proportion of hydrocarbon solvent and thereby 'recovering from the sludge sulphuric` acid having a specific gravity of about 500 to 60O Baume.

13. The process of recovering sulphuric acid from acid sludges obtained from crude oils, as hereinabove described, which consists in mixing a proportion of such sludge with solvent naphtha and thereby recovering from the sludge sulphuric acid.

14. The process of recovering sulphuric acid from acid sludges obtained from crude oils, the acid in said sludges being of a specic gravity of not less than 50 Baume as hereinabove described, -Which consists in mixing a proportion of such sludge with hydrocarbon solvent and thereby recovering from the sludge the sulphuricacid Without substantial dilution thereof.

15. The process of recovering sulphuric acid from acid sludges obtained from crude oils, as hereinabove described, which consists in subjecting such sludges to treatment by a hydrocarbon solvent and by such solvent treatment eifecting the recovery from the sludge of the sulphuric acid.

16. The process of recovering acid from acid sludges obtained from crude oils, as hereinabove described, which consists in subjecting such sludges to treatment by a hydrocarbon solvent and by such solvent treatment recovering the acid from such sludges.

17. The process o'l` recovering acid from acid sludges obtained from crude oils, as hereinabove described, Which consists in subjecting such sludges to treatment by solvent naphtha and by such solvent treatment recovering the acid from such sludges.

18. The solid hydrocarbon product obtained from the solvent treatment of acid crude oil sludges, Which product contains polymerized hydrocarbons, sulphonated hydrocarbons and oxidized hydrocarbons, and is characterized by a plastic and adhesive nature, an absence of hydrolized bodies, a substantially complete solubility in gasolene of 60O Baume and an iodine value of substantially 27.

19. The solid hydrocarbon product containing polymerized hydrocarbons, sulphonated hydrocarbons and oxidized hydrocarbons, and characterized by a plastic and adhesive nature, an absence of hydrolized bodies, a substantially complete solubilityin gasolene of 60O Baume and an iodine value of substantially 27.

20. The solid hydrocarbon product containing polymerized hydrocarbons, sulphonated hydrocarbons and oxidized hydrocarbons, and characterized by an absence of hydrolized bodies, and a substantially complete solubility in gasolene of 60O Baume.

21. The solid hydrocarbon product containing polymerized hydrocarbons, sulphonated hydrocarbons and oxidized hydrocarbons, and characterized by an absence of hydrolized bodies.

FREDERICK SALATHE. 

